Mass. Gen. Laws ch. 41 § 19E
In any city or town in which the clerk has been given permanent tenure by the acceptance of the provisions of section nineteen B, such tenure in office shall be effective only during the incumbency of the person who held such office at the time said section was accepted and it shall not extend to his successor in office. Whenever any vacancy shall occur in the office of city or town clerk in any city or town by reason of the death, retirement, resignation, attaining age seventy or removal of an incumbent who had been given such tenure, his successor, in the case of cities, shall be appointed, or elected as provided by the charter of such city or by the applicable provisions of any general or special law in effect at the time such vacancy occurs; and, in the case of towns, his successor shall be elected in accordance with the provisions of section one of chapter forty-one of the General Laws. Whenever such vacancy occurs in the office of clerk in any town, or in any city in which it is provided by law or by its charter that the city clerk shall be elected by popular vote at a regular election, a temporary clerk may be appointed as provided by section fourteen of said chapter forty-one to serve until the qualification of such duly elected city or town clerk as shall be elected at the next regular annual or biennial election at which such officer shall be elected.
Nothing herein contained, however, shall be construed to prohibit any successor in such office of city or town clerk from obtaining tenure after serving continuously not less than five years by the filing of another petition requesting acceptance of section nineteen B and its acceptance by the registered voters as set forth in section nineteen C.
Mass. Gen. Laws ch. 41, § 19E